Super Elinvar effect in Nb-Mo binary alloys

Alloy with temperature-insensitive elastic modulus, i.e. Elinvar effect, is crucial for the high precise equipment, like Gyroscope and tuning-fork sensor. However, the Elinvar effect suffers from an intrinsic hysteresis and narrow temperature-window, as it is generally triggered by a second order phase transition.1 Recently, Yang et al. reported that Co25Ni25(HfTiZr)50 high entropy alloy shows Elinvar effect from 300 to 900 K, owing to its local structure distortion and magnetic-order transition.2 Yang`s result suggests that the disadvantage of Elinvar effect may be avoid, if it can trigger by the local structure distortion only. Here, we reported such result in a simple binary Nb-Mo alloy. It shows a wide-temperature-window Elinvar effect over 1000 Kelvin (300 ~ 1300 K), with no obvious phase transition. The Elinvar effect of Nb-Mo alloy may cause by the unique {112}<111> deformation twins in Nb alloys,3 and deformation twin can lead to a BCC to ω distortion.